All systems go for Curiosity rover on Mars
Nasa engineers have been testing the rover's systems to ensure they survived the landing and can begin uncovering secrets of the red planet
After two weeks of checking instruments, testing software and practising its rock-zapping skills, Curiosity the Mars rover is now taking its first baby steps across the surface of the red planet.
After a hair-raising entry to the planet on August 5 - when Curiosity was lowered to the surface by a descent module that fired rockets to keep it hovering above the Martian surface - extensive testing was needed to ensure all the precautions for the Mars landing were not in vain.
"The first few weeks were set aside for the engineering team to get up to speed, to make sure all the systems and instruments check out OK," said Peter Grindrod, a planetary scientist at University College London, who has been watching every move of the mission.
"They're not in any rush; this mission is meant to last for two Earth years. The first few days are about: Is everything in one piece, are the cameras working?"
Last Tuesday, Curiosity wiggled its front and back sets of wheels. Engineers at Nasa, the US space agency, wanted to make sure all the steering actuators were still working, that the wheel motors were turning. Every move was watched by the engineers via the rover's on-board cameras.
The engineers have also been upgrading software and getting used to using the robotic arm, which is two metres long and weighs 30kg - much bigger and trickier to manoeuvre than the arms on the previous Mars rovers, Spirit and Opportunity.
"There was a bit of getting used to using the arm under Martian gravity and calibrating the movements exactly because they're going to deliver samples to these instruments on board, so they need to be very precise," Grindrod said.
When Curiosity makes its first drive, it will be just a few metres forward. It will then make a 90-degree turn and drive back for a few metres.
The science experiments will start when the rover gets to its first place of interest, an area called Glenelg, about 400 metres to the east of where it is now.
Grindrod said Nasa would also probably have a good look at the blast marks created when the descent rockets moved away the dust during the landing. The landing uncovered interesting-looking bedrock.
The rover has already fired its laser into the landing site and taken pictures and data, but Nasa has not yet revealed any of the measurements.
"All the other rocks on the surface look like the Mars everyone knows from Viking through to Spirit," Grindrod said. "The ones that have been revealed [at the blast marks] look like they might be slightly lighter-toned and might suggest a different composition.
"The most interesting thing is that these don't look like rocks that are just sat on the surface and have ended up there, either thrown out from a meteorite impact or having been delivered by erosion. These things look like they might be in situ, where they formed."
Geologists can use in situ rocks to get a good idea of the history of that part of the planet - when it formed, for example, and in what conditions.
It could be a year before Curiosity gets to its main mission: Mount Sharp.
"There [are] two main things that make Mount Sharp interesting. It's 5km of layered rock, which are probably sediments. We're not sure how they are laid down but, on Earth, those layers are very good at revealing the environment in which they formed."
The other thing that swayed it for Gale Crater as the landing site was the chemistry scientists saw from orbit. "Near the bottom there is evidence that water was around at some point in some form. If you go to the top, it's dry," Grindrod said.
Last week, Nasa announced that it would send a low-cost lander to Mars in 2016 to look deep into the planet's interior.